Template‐ and Surfactant‐free Room Temperature Synthesis of Self‐Assembled 3D Pt Nanoflowers from Single‐Crystal Nanowires

3D Pt nanoflowers, which are composed of numerous single-crystal nanowires, are successfully synthesized by a facile chemical procedure, at room temperature, without surfactant or template. The Pt nanoflowers adhere to carbon paper, exhibiting an enlarged electroactive surface area comparable to that of a commercial Pt/C electrode.